RESUMO
In case of a nuclear emergency, many samples need to be measured in a short time period. Therefore, it is of vital importance to have a quick and reliable (screening)method. Most methods to determine total beta activity are time-consuming because of extensive sample preparation, such as ashing. In this article three different rapid screening methods for beta emitting nuclides in agriculture, livestock and fishery products were tested and compared to each other, and to an accurate but more time consuming reference method. The goal was to find the method with the optimal trade-off between accuracy, speed and minimal detectable activity (MDA). All of the methods rely on liquid scintillation counting (LSC) or Cerenkov counting, and differ mainly in sample preparation. For matrices with little or no colour, the direct LSC-method is the most accurate and fastest option, while for darker coloured samples this method is not suitable because of high colour quenching. For such samples, two additional methods using a microwave digestion during sample preparation, produced good results.
